Method of and appliance for polishing glass and the like substances



W. TAYLOR.

METHOD OF AND APPLIANCE FOR POLISHING GLASS AND THE LIKE SUBSTANCES.

APPLICATION FILED MAY 17. 1919. I

1 .409.888. Patented Mar. 14, 1922.

2 SHEETS-SHEET I.

lA/VEA/TOR (um-4W M 9 flwgaz w N. IAYLOR.

METHOD OF AND APPLIANCE FOR POLISHING GLASS AND THE LIKE SUBSTANCES.APFLICATlON FILED MAY 1?, 1919.

1,409,888. Patented Mar. 14, 1922.

2 SHhETSSHEET Z.

M/VE/ITOR W/TNESSEJ'.

77 M M; i W47 UNITED STATES PATENT OFFICE.

WILLIAM TAYLOR, 0F LEICESTER, ENGLAND.

METHOD OF AND APPLIANCE FOR POLISHING GLASS AND THE LIKE SUBSTANCES.

Application filed Kay 17,

7 '0 all whom it may concern:

Be it known that I, WILLIAM TAYLOR, a subject of the King of GreatBritain, and resident of Stoughton Street Works, Leicester, in thecounty of Leicester, England, have invented a certain new and usefulImprovement in Methods of and A pliances for Polishing Glass and thelike i ubstances, of which the following is a specification.

This invention relates to methods of, and means for, polishing glass andthe like substances by means of powdered abrasive such as rouge'in aliquid vehicle or lubricant, and its object is to provide a method andmeans whereby, during the process of polishing, the supply of lubricant,or lubricant and abrasive, is effected automatically as required.

This may be done, according to my invention, by taking advantage of thevarying adhesion, that 1s, the frictional resistance to relativemovement, which takes place between the polishing tool and the work asthe polisher becomes dry.

In polishing machines means are provided for effecting a relative motionof the tool and work to cause the polishing. Such means may comprisemeans for moving one of these members while retaining the otherstationary, or means for moving each of the members. It should beunderstood that the expression means for causing a relative motion ofthe polishing members is intended to cover any means for controlling themovement or position of each member in such a way that the contactingsurfaces of the members move with respect to one another.

The manner in which the frictional resistance between the polishing tooland the work varies depends to some extent upon the material of whichthe polishing tool is made. For the sake of illustration, I. shalldescribe the use of the invention in connection with polishing machinesin which the face of the polishing tool is formed of wax or any similarsubstance which is comparatively impervious to the lubricant, althoughthe invention is by no means limited to use in connection with suchpolishers. \Vlien tools of such materials are used, the frictionalresistance between the tool and the work generally increases as thepolisher becomes dry.

In machinery for polishing glass it is usual to employ a rubber orpolisher having Specification of Letters Patent.

1919. Serial No. 297,777.

a face whose form is a counterpart of that required on the work, thepolisher being moved about the work by means of a crank. Onamethod,therefore, according to which my inventlon may be carried out is toconnect the crank to the crank-shaft which operates it, by means of adynamometer which may be adjustable so that it shall yield when, as thepolisher becomes dry, the adhesion between the polisher and the workrises to a predetermined amount, and the yielding of the dynamometer maybe made to actuate, for example, a pneumaticallycontrolled valve whichmay supply liquid on to the surface of the work or polisher. Such liquidmay contain abrasive in suspension 1n known manner.

Another method which maybe used to control the supply of liquid is toprovide, for moving the polishing tool, a non-rotary finger adapted toyield laterally in one direction against the action of a spring, whichmay be adjustable. held by the spring in its seating in an actuatmgmember, but as the adhesion between the polisher and the work rises tothe predetermined amount, the finger is dis laced thereby from itsseating and may be adiipted to actuate at such time the liquid supplyvalve or equivalent device.

In some polishing machines the work is held on a suitable holder on aslowly-rotating spindle, and the polisher is moved in a circular pathupon the moving work, so that relatively they describe a cylindricalpath. At one part of such circular path the velocity of rubbing is thesum of the velocities of the two motions, and at other parts it is lessthan the sum and thus the resistance to motion which increases as awhole as the polisher becomes dry varies continuously from a maximum toa minimum during each complete movement of the polisher.

This fact I may utilize, according to the present invention, in order tosupply the liquid intermittently and as required at one part only of themotion of the polisher, for example, at the point in such motion atwhich, momentarily, the surface of the work is most exposed by themovement of the polisher. In this way I economize lubricant andabrasive.

Other devices may, of course, be used to control the supply of liquid atthe critical time, and means other than a pneumatically Normally thefinger is Patented Mar. 14, 1922.

. tubular bar controlled valve may be used for supplying the liquid orabrasive.

In the accompanying drawings, which i1- lustrate by way of example onemeans of carrying out the invention, Figure 1 is a diagrammatic andpartial view showing in plan three lens-polishing units of a rangecomprised in a single polishing machine. Figure 2 is a diagrammaticfront elevation of the same. showing also means for maintainingcirculation in the lubricant feedpipe. Figures 3 and 4 are respectivelya detailed plan view and side elevation of part of the apparatus apcaring in Figure 1; Figure 5 is a detaile plan view of one of thenozzles appearing in Figure 1; Figure 6 is a horizontal longitudinalsection of the part of the apparatus shown in Figure 3;

igure 7 is a view similar to Figure 5 show ing a modified form ofnozzle. Figures 3, 4, 5, 6 and 7 being drawn to a larger scale thanFigures 1 and 2.

In Figures 1 and 2 a and 6 represent, in the case of each lens-polishingunit,two toolmembers to either of which the work may be attached whilstthe other member is the polisher; it being understood that there iscaused by known means a relative movement of these members whereb thecoacting surfaces of the work and po ishing member are rubbed togethermechanically. c are nozzles su plied from a pipe 0 with lubricant (forIn ricant and abrasive) and adapted to project the same onto the exposedportion of the member a; whilst Figure 1 also shows at e, in the case ofeach lens-polishing unit, that part of the operating machine whichserves to carry a finger (usually ball-pointed) whereby the member 6 isengaged and moved, and whereby in accordance with the present inventiona spray of lubricant (and rouge or other abrasive) is pneumaticallycontrolled as hereinafter explained.

The portion 6 of the mechanism (Figure 1) is illustrated in detail inFigures 3 and 4, wherein (Z is a bar adjustably clamped, by means of ascrew 9, in an arm 7 whereby the upper tool-member b is moved over thesurface of the lower tool-member a in a substantially circular path byusual mechanically-actuated means (not shown); the bar d, which istubular, being connected by a flexible tube It to an air-pipe (plenum orvacuum) hereinafter mentioned. The bard has an arm d which carries apivot pin 2' whereon a link j is pivoted, the ink j hav ing a hole j inwhich a ball-pointed finger 7' for engaging and moving the member I; isadjustably clamped by means of a screw 7' The link 7' also carries avalve j adapted to control an opening at the outer end of the thisopening being surrounded by a bush d (preferably of fibre or the like)adapted to afford an elastic seating for the valve 3'; The link 7' ismoved in the direction to cause the valve j to close against its seating(Z by the action of a helical spring 7: which is contained in a tubularholder Al pivoted at in to the bar (I, the spring 7.; being icld undercompression between a ball which rests in a peripheral groove on thepivot-pin 70 and a plunger k which fits slidably in the holder 12 and isforced by the spring outwards against the arc-uate edge of an arm 7' onthe link j. The ball 70* serves to retain the holder 70 upon thepivot-pin k whilst permitting angular adjustment, of the holder aboutthe pivot; such adjustment which may be determined with the aid ofgraduations marked upon the arm j as indicated, serving to vary asdesired the turning-moment exerted,about the axis i, by the spring itagainst the arm j and link j, and consequently to vary the effectivepressure with which not only is the ball-pointed finger j retained innormal position but also the valve j is held closed against its seating(Z yet without altering the stress of the spring is itself. For thepurpose of limiting the movement of the link about the pivot z' anadjustable stop (Z may be provided on an arm d of the bar (Z.

One of the spraying-nozzles c on the pipe 0 (Figures 1 and 2), is shownin greater detail in Figure 5, which shows the nozzle outlet ascontrolled by a needle-valve c the stem 0 of which, extendingacross thepipe c is attached to a piston c fitted to slide in a cylinder 0 Thepiston c is urged by a spring a in the direction to open the valve 0 theopening movement being adjustably limited by a screw 0 which passesthrough the rear closure 0 of the cylinder 0 whilst by way of a flexibletube 0 the cylinder communicates at its rear end (i. e. at the side ofthe piston c opposite to the spring a) with a branch 19 on a pipe pwhich is supplied with air under pressure from any convenient source.The branch 70 is adjustably controlled by a throttle-valve 32 betweenwhich and the junction of the flexible tube 0 the flexible tube It(already mentioned) is connected to the branch 19 the adjustment of thevalve p serving to determine the volume and duration of the emissionfrom the nozzle 0. A constant circulation of lubricant (or lubricant andabrasive) is maintained in the pipe 0 but so long as the air in thebranch p remains at a predetermined pressure, the air-pressure withinthe cylinder 0 is sufiicient to overcome the force of the spring 0 andthe needle-valve 0 remains closed. When, however, the adhesion betweenthe work and the polishingtool (i. e. between the members a and b) risesso far as to cause the link 7' to move so as to open the valve j, airescapes through this valve from the branch h, thus reducing theair-pressure within the tube 0 and cylinder with the result that theneedle-valve 0 is opened by the spring 0 so as to permit a jet oflubricant (or lubricant and abrasive) to be projected onto thetool-member a from the nozzle 0.

If, instead of a plenum, or positive pressure, a vacuum, or negativepressure is maintained in the air-pipe p, the tube 0 would be connectedto the cylinder 0 at the same side of the piston c as the spring a asshown in figure 7; the action of the spring 0 being in such casenormally opposed by the vacuum in the cylinder 0", but permitted tobecome effective when, owing to the opening of the valve 7", air isadmitted through the tube It to the branch 0 The term pressure as usedin the claims is to be understood as including ne ative as well aspositive pressure.

igure 2 illustrates one arrangement for maintaining a constantcirculation of rouge and water (or equivalent abrasive and lubricant)through the pipe 0 The mixture of rouge and water is contained in a tankZ wherein is mounted a centrifugal pump Z driven by power from anyconvenient source, as for example by a belt Z passing over aguide-pulley Z and around a pulley Z on the pump-spindle as indicated.The outlet on of the pump is connected to the circulationipe 0 which maybe of rubber so as to fhcilitate the independent adjustment of thepositions of the nozzles c, and this pipe '0 terminates in an uprightstand-pipe n affording a constant head of liquid; the pipe n deliveringinto the mouth 0 of a return-pipe 0 through which the surplus liquid isled back to the tank Z. Constant and fairly rapid circulation isnecessary in order to prevent deposition of the abrasive in the pipe 0When the apparatus is in use and the surfaces of a pair of tool-membersa and b have been moistened (either by the jet from the nozzle 0, orotherwise) polishing proceeds until the polishing-tool becomessufficiently dry to render the polishing action most efficient; a stagewhich is easily recognized by an experienced attendant. At this momentthe point whereat the spring it exerts its thrust against the arm j ofthe link j may be so set that, at each to-and-fro movement of the finger7' the valve j is caused to open so as to release air from the tubes hand c and thus bring about the opening of the needle -valve 0 and theconsequent discharge of lubricant and abrasive from the nozzle c. Whensufficient lubricant has been deposited upon the surface of thetool-member, the adhesion and resulting traction between them is sodiminished that the valve j is permitted to close under the action ofthe spring In with the result that the air-pressure within the tubes 71-and 0 again rises (at a rate dependent upon the adjustment of thethrottle-valve p until, the force of the spring 0 being eventuallyovercome, the

needle-valve c closes and stops the discharge from the nozzle 0.Preferably, the direction in which the finger j is movable to open thevalve 7' is such that the valve is opened and the jet issues from thenozzle 0 at the moment when the adjacent portion of the surface of thetool-member a is most exposed by the withdrawal therefrom of thetool-member b.

I claim I l. The method of controlling the supply of liquid lubricant inthe polishing of a surface by means of a polishing member, saidpolishing member and the work being moved relatively to one another toeffect the polishing, which method comprises increasing the supply ofthe liquid to said surface when the frictional resistance between thesurfaces of the polishing member and the work exceeds a predeterminedamount, and decreasing the supply when said frictional resistance fallsbelow a predetermined amount.

2. The method of controlling the supply of liquid lubricant and abrasive1n the polishing of a surface by means of a polishing member, saidpolishing member and the work being moved relatively to one another toeffect the polishing, which method comprises circulating the liquid in acontainer to keep the abrasive in suspension in the liquid, increasingthe supply of the liquid and abrasive to one of said surfaces when thefrictional resistance between the surfaces of the polishing member andthe work exceeds a pre-determined amount, and decreasing the supply whensaid frictional resistance falls below a predetermined amount.

3. The method of controlling the supply of liquid lubricant in thepolishing of a surface by means of a polishing member, said polishingmember and the work being moved relatively to one another to effect thepolishing, which method comprises utilizing the variation of frictionalresistance between the surfaces of the work and polishing member toeffect variation of the supply of lubricant.

4. The method of supplying liquid lubricant in the polishing of surfacesby means of a polishing member, said polishing member and the work beingmoved relatively to one another to effect the polishing. which methodcomprises supplying the liquid automatically in predetermined amount andintermittently whenever the frictional resistance between the surfacesof the work and polishing member reaches a predetermined limit.

5. The method of supplying liquid lubricant in the polishing of surfacesby means of a polishing member, said polishing member and the work beingmoved relatively to one another to effect the polishing, which methodcomprises supplying the liquid automatically, intermittently. and at apredetermined rate for a predetermined interval of time, whenever thefrictional resistance between'the surfaces of the work and polishingmember reaches a predetermined limit.

6. In apparatus for supplying lubricant to a polishing machine havingcooperati work holding and polishing members an means for causingrelative motion between said members for producing relative move mentbetween the coacting surfaces of the polishing member and the work, thecombination of means for supplying lubricant to on of'said surfaces, andmeans operated by variation of the friction between said surfaces forcontrolling the supply of lubricant.

7. In a paratus for supplying lubricant to a polis mg machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishin member and the work, thecombination 0 lubricant supply means having an outlet fordischarginglubricant onto one of said surfaces, a controlling valve for saidoutlet, means for exerting constant yielding pressure on said. valve 1nthe direction to cause it to open, holding means for keeping said valvenormally closed, and controlling means operated by variation of thefriction between said surfaces to render said holding means inoperativeand permit said valve to open when the friction between said surfacesreaches a predetermined value.

8. In a paratus for supplying lubricant to a polis mg machine havingcooperative work holding and polishing members and means for causingrelative motion between said members for producing relative move mentbetween the coacting surfaces of the polishing member and the work, thecomination of means for sup lying lubricant to one of said surfaces, anmeans for controllin the supply of lubricant, connected to sai movingmeans and operated by variation in the load on said moving meansresulting from variation in friction between the work and the olishingmember.

9. In a paratus or supplying lubricant to a polis ing machine havingcooperating work holding and polishing members and means for causingrelative motion between said cooperating members for producing relativemovement between the coacting surfaces of the polishing member and thework, said means including a moving member, the combination of anengaging member adapted to engage one of the aforesaid cooperatingmembers and transmit motion of the moving member thereto, means adaptedto connect said engaging member to said moving member and permit limitedmovement of the engaging member relative thereto, said means mcluding aspring adapted to resist the load on said engaging member resulting fromthe friction between the surfaces of the polishing member and the work,means for supplying lubricant to one of said surfaces, and means forcontrolling the supply of lubricant adaptedto be actuated by movement ofthe engaging member relative to'the moving member.

10. Inapparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, alubricant supply means having an outlet arranged .to discharge lubricanton to one of said surfaces, a normall closed valve controlling saidoutlet, an automatic means operated by variation of the friction betweensaid surfaces to open said valve when said friction reaches apredetermined value.

11. In apparatus for supplying lubricant and abrasive to a polishingmachine having a pluralit of work holders and corresponding polis ingmembers, each work holder and corresponding polishing member beingadapted to have a relative motion for producing relative movementbetween the coacting surfaces of the polishing member and the work, acirculating s stem comprising a pipe provided with a p urality ofoutlets arranged to supply lubricant and abrasive to said coactingsurfaces, and means for maintaining a constant circulation of lubricantand abrasive in said system, independent of the flow through saidoutlets, at a velocity sufficient to prevent deposition of the abrasive.

12. In apparatus for supplying lubricant and abrasive to a polishingmachine havin a plurality of work holders and correspon ing polishingmembers, each work holder and corresponding polishin member beingadapted to have a relative motion for producing relative movementbetween the coacting surfaces of the polishing member and the work, acirculating system comprising a pipe extending adjacent to said workholders and polishing members and provided with a plurality of outletsarranged to supply lubricant and abrasive to their coacting surfaces,means for maintainin a constant circulation of lubricant and a rasive insaid system at a velocity sufficient to prevent deposition of theabrasive a valve for controlling each of said outlets, and means forintermittently opening said valves.

13. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfacesof the polishing member and the work, alubricant supply means having an outlet arranged to discharge lubricantonto one of said surfaces, a valve controlling said outlet, automaticmeans operated by variation of the friction between said surfaces toopen said valve when said friction reaches a predetermined value, meansfor closing said valve, and means adjustable for varying the amount oflubricant discharged upon each opening of the valve.

14. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, alubricant supply means having an outlet arranged to discharge lubricanton to one of said surfaces, a valve controlling said outlet, automaticmeans operated by variation of the friction between said surfaces toopen said valve when said friction reaches a predetermined value, andmeans adjustable for varying the time during which the valve remainsopen.

15. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, alubricant supply means having an outlet arranged to discharge lubricanton to one of said surfaces, automatic means operated by variation of thefriction between said surfaces for controlling the supply of lubricant,and

means adjustable for varying the rate of flow of lubricant through saidoutlet.

16. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members, and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, thecombination of means controlled by variation of the friction between thesurface of the polishing member and the work to supply lubricant to oneof said surfaces when said friction reaches a predetermined value, andmeans adjustable for varying said predetermined value.

17. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the olishing member and the work, thecomination of means for supplying lubricant to one of said surfaces, andmeans operated by variation of the friction between said surfaces forcontrolling the supply of lubricant,

said last mentioned means being arranged to cause lubricant to besupplied to such surface at the time when and place where it is exposedby the relative motion between the members.

18. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, thecombination of lubricant supply means having an outlet for discharginglubricant on to one of said surfaces, a controlling valve for saidoutlet, means for applying constant yielding pressure tending to movesaid valve in one direction, means for opposing to said con-- stantyielding pressure pneumatic pressure tending to move said valve in theopposite direction, and means operated by variation of the frictionbetween said surfaces for varying said pneumatic pressure and therebyactuating said valve.

19. In apparatus for supplying lubricant to a polishing machine havingcooperatin work holding and polishing members an means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, thecombination of lubricant supply means having an outlet for discharginglubricant on to one of said surfaces, a controlling valve for saidoutlet, means for exerting constant yielding pressure on said valve inthe direction to cause it to open, pneumatically operated means forkeeping said valve normally closed and means for supplying pneumaticpressure thereto, means providing a normally closed vent, andcontrolling means operated by variation of the friction between saidsurfaces to open said vent to relieve said pneumatic pressure and permitsaid valve to open when thefriction between said surfaces reaches apredetermined value.

20. In .apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members and means for causingrelative motion between said members for producing relative movementbetween the coacting surfaces of the polishing member and the work, thecombination of lubricant supply means having an outlet for discharginglubricant on to one of said surfaces, a controlling valve for saidoutlet, means for exerting constant yielding pressure on said valve inthe direction to cause it to open, pneumatically operated means forkeeping said valve normally closed and means for supplyin pneumaticpressure thereto, means provi ing a normally closed vent, andcontrolling means operated by variation of the friction between saidsurfaces to open said vent to rehave said pneumatic pressure and permitsaid valve to open when the friction be tween said surfaces reaches apredetermined value, and an adjustable throttle controlling thepneumatic pressure supply and operative to vary the period of operationof said valve by varying the rate at which, after the pneumatic pressurein the valve closing means has been relieved by the opening of the vent,such pressure is restored.

21. In apparatus for supplying lubricant to a polishing machine havingcooperating work holding and polishing members, and means for causingrelative motion between said members for producing relative movementbetween the contacting surfaces of the polishing member and the work,the combination of a yieldable element in the means for causing suchrelative motion adapted to yield under a predetermined force, means forsupplying lubricant to one of said surfaces, and means for controllingthe supply of lubricant actuated by the yielding of said yieldableelement.

22. In apparatus for supplying lubricant to a polishing machine havingcooperatin work holding and polishing members, and means for causingrelative motion between said members for producing relative movementbetween the contacting surfaces of the polishing member and the work,the combination of a yieldable element in the means for causing suchrelative motion adapted to yield under a predetermined force, means foradjusting said yieldable element so as to vary the predetermined forceunder which it is adapted to yield, means for supplying lubricant to oneof said surfaces, and means for controlling the supply of lubricantactuated by the yielding of said yieldable element.

23. In a polishing machine having 00- operating work holding andpolishing members and means for causing relative motion between saidmembers for producing relative movement between the coacting surfaces ofthe polishing member and the work, means for maintaining frictionbetween the surfaces of the work and the polishing member approximatelyconstant comprising the combination of means for va ing the frictionbetween said surfaces, an means operated by variation of the frictionbetween said surfaces for controlling the operation of said friction varin means.

IL IAM TAYLOR.

